<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8" />
		<title>3.回忆sort</title>
	</head>
	<body>
		<script type="text/javascript" >
			let arr = [8,5,3,4,2,6,7,1,9]
			arr.sort((a,b)=>{return b - a})

		</script>
	</body>
</html>